(1) Field of the Invention
The present invention generally relates to an evaporated fuel control apparatus, and more particularly to an apparatus for preventing evaporated fuel of a fuel tank of an automotive vehicle from escaping to the atmosphere even when the vehicle stays at a high temperature for an extended period.
(2) Description of the Related Art
Japanese Laid-Open Patent Publication No. 60-153463 discloses an evaporated fuel control device in which a fuel tank is connected to a canister having an opening that is open to the atmosphere, so that the fuel tank communicates with the atmosphere via the opening of the canister. When the temperature of fuel within the fuel tank becomes higher, a certain amount of fuel is evaporated and the internal pressure of the fuel tank is increased. As a certain amount of air is fed from the fuel tank into the atmosphere via the opening of the canister due to the increased pressure of the fuel tank, the internal pressure of the fuel tank can be maintained at a constant level. As the canister provided between the fuel tank and an intake passage of the engine contains an absorbent for absorbing evaporated fuel, the evaporated fuel supplied from the fuel tank is absorbed by the canister, thus preventing the evaporated fuel of the fuel tank from escaping to the atmosphere.
However, when the vehicle is exposed to hot weather for a long period, for example while parked, the temperature of fuel within the fuel tank becomes very high, and an increasing amount of fuel in the fuel tank is actively evaporated. In order to capture all the evaporated fuel supplied from the fuel tank, it is necessary to utilize a canister capable of storing a very large amount of evaporated fuel. However, the mounting space for mounting parts on an automotive vehicle is limited, and it is difficult to mount a large-capacity canister on the automotive vehicle.